<!DOCTYPE html>
<html lang="zh-CN">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<style>
    div {
        width: 300px;
        height: 300px;
        background-color: pink;

        /* 分别设置盒子的边框线 */
        border-top: 5px solid #000;
        border-left: 5px dashed green;
        border-bottom: 5px dotted yellow;

        /* 取消边框线 */
        border-right: none;

    }
</style>

<body>
    <div>盒子模型</div>
</body>

</html>